Question: Express your answer as a mixed number simplified to lowest terms. $10\dfrac{2}{5}+8\dfrac{2}{5} = {?}$
Explanation: Separate the whole numbers from the fractional parts: $= {10} + {\dfrac{2}{5}} + {8} + {\dfrac{2}{5}}$ Bring the whole numbers together and the fractions together: $= {10} + {8} + {\dfrac{2}{5}} + {\dfrac{2}{5}}$ Add the whole numbers: $=18 + {\dfrac{2}{5}} + {\dfrac{2}{5}}$ Add the fractions: $= 18+\dfrac{4}{5}$ Combine the whole and fractional parts into a mixed number: $= 18\dfrac{4}{5}$